1. Field of the Invention
The present invention relates a key determination apparatus for determining the key of a musical composition and a storage medium storing a key determination program.
2. Description of the Related Art
In electronic musical instruments with keyboards, as in the piano or organ, a melody is played mainly with the right hand and the accompaniment is played with the left hand. For playing the piano, it is required to practice to be able to move the fingers of the right hand and the fingers of the left hand each independently according to music. Meanwhile, for playing the organ, it is required to press a plurality of keys (manipulators) which constitute a chord correctly with the left hand. In order to play the organ, it requires some practice to play chords.
As described above, in the playing methods for each of the piano and the organ, it requires an appropriate amount of practice to move the right hand and left hand both at the same time. Especially, although beginner players feel it to move the fingers of the right hand for melodies, many of them feel it difficult to press the respective manipulators with the left hand to accompany the right hand. Under these circumstances, there is a demand for an electronic musical instrument such that when the player plays a melody with the right hand, the instrument automatically forms an accompaniment to be played with the left hand, and plays it along the melody.
For example, U.S. Pat. No. 5,296,644 proposes an instrument which stores in advance musical note data of a musical composition for a plurality of sections, and when the chord name is given to the second section of the musical note data, the new chord name is determined with reference to the key data, the musical note data corresponding to the second section, the musical note data of the first section and the chord name previously given to the second section.
It should be noted here that a musical composition does not always have a fixed key, but in many compositions, the starting key changes to another key within one composition by modulation. When the key is modulated, it is necessary to detect to what key the composition is modulated and obtain the new key before the determination of the chord name. Further, at the start of a musical composition or a phrase, it is in many cases difficult to determine in what key the composition or phrase is started.
For example, U.S. Pat. No. 5,302,777 discloses a technique of determining a new key by analyzing the chord pattern between a new chord and a chord preceding the new chord. Further, U.S. Pat. No. 5,296,644 as well discloses a technique of detecting a key based on a determined chord progress.
However, each of the above-described prior art techniques requires to obtain a determined chord progress for detecting the key, and entails a problem that the key cannot be detected simply from a melody sequence.